EP2662483A1 - Device and process for stamping a fabric sheet of a sewing machine - Google Patents

Abstract

The sheet punching apparatus has a sheet (23) that is slidably and transversely placed between sewing machine head (1) and needle plate (7) along the needle bar axis. A punching die (5b) of a punching tool is matched with the punch portion (5a). A gap in which the sheet is displaced for punching, is formed in the normal position between punch portion and punching die. A waste portion of the sheet is punched out to a waste container (9) by moving from punching die from initial position into end position. An independent claim is included for method for punching sheet.

Description

The invention relates to an apparatus and a method for punching a sheet with a sewing machine according to the preamble of claims 1 and 10.

Sewing machines usually include a stand on which a forearm and an upper arm project laterally. The end region of the upper arm is designed as a machine head, on the underside of which a needle bar which can be moved up and down and a presser foot rod protrude. On the forearm, which serves as Nähgutauflage, an exchangeable throat plate is arranged below the machine head. It comprises a puncture opening for the sewing needle and recesses for the feed dog of a transporter, which advance the sewing material during sewing coordinated with the needle bar movement periodically in a sewing direction transverse to the movement of the needle bar. The material feed through a feed dog can be deactivated on most sewing machines. The movement of the sewing material in the sewing plane can alternatively also be done purely manually, for example. Many sewing machines are also designed to connect an embroidery module. The fabric is clamped in an embroidery frame, which are moved in two orthogonal directions of the sewing plane can. When embroidering the embroidery frame is moved in dependence of a given embroidery pattern by two independent drives for each stitch to be formed in the required position.

With appropriate training, other tools for processing a fabric can be connected to the sewing machine as an alternative to sewing needles. It is for example from the European patent application EP2221409A1 known to attach a tool such as a textile writer by means of a holding device on the Nähfussstange the sewing machine and to use this tool instead of a sewing needle for processing a textile or non-textile fabric. From the DE102010020623A1 is a connectable with a sewing machine and influenced by the sewing machine embedding device for decorative elements such as rhinestones or sequins known. The decorative elements are stored in magazines or on straps and are applied by the mounting device individually at predetermined positions on the fabric. The sheet may be, for example, a self-adhesive transfer film. The decorative elements are first applied in the respectively desired arrangement on the transfer film, where they temporarily adhere, and then transferred by means of heat to a textile fabric.

Furthermore, the disclosure EP2172585A1 a fastened to the needle bar turning device for a cutting needle. By means of this rotary device, the orientation of the cutting edge of the cutting needle can be changed relative to the material, so that the cutting angle can be adapted to the auszuschneidenden contours on the fabric.

Such machines connectable to the sewing machine make it possible to machine a fabric with different techniques. If a fabric is clamped in an embroidery hoop, its relative position and orientation on the hoop can be maintained for several steps. It is also possible to process successively several different fabrics in one or more steps. In this case, the relative coordinates used with respect to the embroidery frame in the processing of each of the workpieces can be coordinated.

An object of the present invention is to provide a punching device for a sewing machine and a method for punching portions of a sheet. When punching small subregions or waste parts are usually completely separated from the rest of the fabric. The punched out waste parts If they remain lying on the fabric, they can hamper further processing or even make it impossible. A further object of the invention is therefore to design the punching device such that punched parts can not cause any obstructions or disturbances.

These objects are achieved by a device and by a method for punching a sheet according to the features of patent claims 1 and 10.

The punching device comprises a punch and a stamping die corresponding to this punch. Preferably, the punch instead of a sewing needle on the needle bar and the punching die in the range of Nähgutauflage, preferably directly to the needle plate, attached. The relative positions and optionally orientations of the punch and the punch die are coordinated so that between the punch and die a clearance remains when the needle bar is in an upper position, and that the punch on lowering the needle bar in one of Shape and size of the punch corresponding recess is inserted. From a workpiece or fabric to be machined, a waste part is punched out in the area of the punching tool. So that this does not fall on the fabric and can hinder the further processing of the fabric, The punching tool comprises a container for receiving the waste parts. Depending on the design of the punching tool, this waste container can be arranged in the region of the punching die or in the region of the punching punch. Preferably, the waste container is formed like a can and comprises means for fixing to the needle plate in a defined position. The punching die with the recess for the punch can be designed as a removable or replaceable lid of the waste container. Depending on the shape and size of the punch, the appropriate punching die can be placed as a lid on the waste container.

In an alternative embodiment of the punch, the punch in the throat plate and the punch die are held on the needle bar. Again, the waste container is arranged adjacent to the punching die or on the punch, or the punching die or the punch forms part of the waste container.

The fabric to be processed is preferably clamped in an embroidery hoop or held in a corresponding other frame, which is movable and positionable in two directions of a working plane transverse to the needle bar axis, in particular in a vertically arranged below the needle bar XY plane according to predetermined criteria. The attachment of the fabric to the hoop is done by clamping between a inner frame and an outer frame, wherein the sheet is optionally stretched over the upper edge of the inner frame or over the lower edge thereof. A fabric held in a defined position on the hoop can be processed in coordinated fashion in several steps with different tools. For example, holes with different sizes and / or shapes can be punched out of the fabric. In particular, stamped gratings can be produced in this way, which can be used as pattern templates for rhinestones of the same or different size. The rhinestones are then inserted into the holes of the stamped grid. Preferably, stencils are produced whose holes are all the same size according to the respective size of the rhinestones to be picked up, wherein the hole diameter is slightly or a few tenths of a millimeter larger than the maximum diameter of these rhinestones. The templates are glued to a flat surface such as a cardboard surface. The rhinestones are then brought as bulk material on the prepared lead frame and conveyed by brushing into the holes of the stamped grid. The rhinestones are formed approximately frustoconical. When brushing only those rhinestones remain in the holes of the stamped grid, the base side with the larger diameter is below. The other rhinestones will be when brushing away from the holes again. Subsequently, a self-adhesive transfer film is glued to the top of the rhinestones, so that they can be transferred in the desired arrangement to a textile or other workpiece.

As an alternative to punched lattices for rhinestones, the punching device can be used to punch out hole patterns in other non-textile or textile fabrics as well. The coordinates of the individual punch holes of a pattern can be specified to the sewing machine or in general the control of the embroidery frame drive analogous to the coordinates of an embroidery pattern. Particularly in the case of thin textiles and / or in the case of large-area punch-outs, these textiles can, for example, be punched before punching. be glued to a releasable carrier film, so that no or only a tolerable minimum delay of the clamped in the hoop frame sheet can occur. Alternatively, a distortion-free further fabric, for example a paper foil, can be clamped into the embroidery frame together with the textile fabric without bonding to stabilize it.

If the waste container is arranged with the punching die on the throat plate, the working plane is higher when punching by a height corresponding to the height of the waste container than the limited by the support surface of the throat plate sewing plane. Preferably, the height of the waste container corresponds therefore about the height of the hoop. If the fabric is clamped in the embroidery frame so that it is flush with its upper edge or flush with the upper edge of the inner frame, its height corresponds to that of the punching die. When moving the hoop, the fabric is displaced without hindrance in the punching plane. Alternatively, the embroidery hoop can comprise retaining means with which it can be fastened in two different positions on the hoop drive, such that the upper edge of the hoop is at the top in one type of fastening and at the bottom in the other type of fastening. Correspondingly, the fabric clamped in the embroidery hoop is in one plane of attachment of the stitch plate or in the sewing plane and in the other in the plane of the punching die or in the punching plane. The mirror-image offset of the punching positions caused by the turning of the embroidery frame can be taken into account or compensated for by the control of the embroidery frame drive, for example, by presetting the respective arrangement of the embroidery frame on the embroidery frame drive as a parameter. The different types of mounting of the embroidery frame on the embroidery frame drive generally cause a transformation of the coordinates of the punching positions. Such transformations may include not only reflections but also displacements and rotations that depend on the arrangement of the holding means on the hoop. In a memory that can be interrogated by the controller stores the corresponding transformation functions. Depending on the embodiment, the controller can determine the respective arrangement of the embroidery frame on the hoop drive, for example, based on a manually presettable setting value of an input interface of the sewing machine or automatically on the basis of sensory measured variables.

The controller can then recalculate the coordinates of the punching positions according to the particular arrangement of the hoop on the hoop drive. Alternatively, with each rearrangement of the hoop or of the fabric held in the hoop, the coordinates can be re-adjusted based on one or more reference points on the fabric. Thus, for example, successively three reference points can be brought to coincide with the puncture site of the sewing needle and the corresponding relative or absolute coordinates of the embroidery frame drive can be detected by the controller. By comparison with previously stored desired coordinates of the reference points, the controller can calculate the arrangement and orientation of the fabric and adjust the coordinates of the individual punching locations accordingly.

This makes it possible to process workpieces in succession coordinated with two or more different tools. In particular, for example, in a textile Garment punching patterns and embroidery patterns can be combined with each other without offset, with the embroidery frame being turned between these work steps.

When punching the fabric is pressed and held analogously to sewing during processing by the punching tool by a presser foot or punching foot against the pad. If the punching plane is higher than the sewing plane, the punching foot is correspondingly shorter. Similar to sewing, the punching foot also performs a jumping movement when punching, so that the workpiece can be moved between the individual punching operations. As an alternative to a separate stamping foot which can be fastened to the sewing foot rod, a resilient hold-down device which can be fastened to the needle bar can also assume the function of the stamping foot. This is then pressed in each case when lowering the needle bar by the spring before the impact of the punch against the workpiece and releases this again after the punch has been pulled up again.

If the resistance of a workpiece during punching is so great that the punch is not able to penetrate the workpiece in a single punching cycle, the sewing machine can be switched to a hammer mode in which the punch presses or hammered several times on the workpiece and in between, for example is pulled up in whole or in part. Alternatively, only the power supply to the punch can be interrupted several times become. The number of repetitions can be selected, for example, depending on the thickness of the respective workpiece. Alternatively, for example, the position of the needle bar can be monitored by sensors and a pulling up of the needle bar can be initiated if the punch has not completely penetrated the workpiece.

In general, the cutting of punch punches have a round cross-section. For each diameter, a suitable punching die with the appropriate diameter is required. Associated punches and punching dies are preferably provided with identical markings.

If the cutting edge of the punch is not rotationally symmetrical, means may be provided for setting a unique orientation of the punch and the punch die. Thus, for example, the punch can be fastened by means of a rotating device to the needle bar and brought into one of a plurality of predetermined rotational angle positions. Such a rotating device is for example in the EP 2172585 disclosed. In an analogous manner, a rotating device for the punching die can be provided. For example, the base element or the bottom of the waste container can be fastened in a defined orientation on the throat plate. The cover with the punching die can be brought relative to the base member in the same predetermined angular positions as the Punching stamp. In this case, the display means, which specify the rotational positions, the punching punch and the die indicate the same value.

In alternative embodiments, the punch in the throat plate and the punch die can be attached to the needle bar. For receiving punched waste parts a waste container is formed at the punching die or at the punch.

With reference to a figure, an embodiment of the invention will be described in more detail below. The figure shows a cross section of a sewing machine with a punching device in the region of the needle bar.

At the bottom of a sewing machine head 1 protrudes a needle bar 3, on which instead of a sewing needle a punch 5a is attached. The lower part of the punch 5a is rotationally symmetric and has a circular cross-section. Its outer diameter is preferably in the range of 0.5mm to 8mm. A mark, for example an engraved number 6 or a color code, clearly identifies the punch 5a. In particular, identical markings can be attached to a punch 5a and the associated punch die 5b. For punching tools that are used for the production of punched gratings or stencils for rhinestones, the markings preferably correspond to the size specifications of matching rhinestones.

A stamping die 5b adapted to this punch 5a is fastened below the needle bar 3 to the needle plate 7 of the sewing machine. The punching die 5b is designed as an exchangeable or exchangeable cover of a can-like waste container 9 and comprises an entry opening 11 corresponding to the shape and size of the punch 5a. In the example of the illustrated punching apparatus, the diameter of the entry opening 11 at the entry point substantially corresponds to that of the punch 5a plus a small game of the order of tenths of a millimeter. Downwards, the diameter of the inlet opening 11 may slightly conically expand, so that punched waste parts of a workpiece easily fall into the waste container 9 and are not jammed during punching. The planar upper side of the punching die 5b is arranged at a distance H1 parallel to the upper side of the throat plate 7 and thus defines a punching plane L2 oriented parallel to the proximity plane L1. At the bottom 9a of the waste container 9, protrudes downwards at least one retaining pin 13, which is preferably fit or with little play in a corresponding recess 7a on the needle plate 7 can be inserted. In the embodiment shown in the figure, the throat plate 7 comprises a round insertion opening for a sewing needle, which is used for insertion of the holding pin 13 becomes. The retaining pin 13 and the inlet opening 11 in the punch die 5b are directly opposite, so that they are arranged after placing the waste container 9 on the needle plate 7 coaxial with the needle bar axis N. In the case of round punching dies 5 a, this is already sufficient for aligning the punching die 5 b relative to the punching punch 5 a because of the rotational symmetry. However, if the punching tool is not rotationally symmetrical, the punching punch 5a and the punching die 5b must additionally be aligned with each other in a defined relative rotational position. Instead of a single round retaining pin 13 may for this purpose, for example, several retaining pins 13 and / or at least one non-rotationally symmetrical retaining pin 13 protrude at the bottom of the bottom 9a. If this or these holding pins 13 are in engagement with corresponding recesses 7a on the needle plate 7, the base 9a or the base element is positioned and aligned in a defined position relative to the needle plate 7. In addition to holding means in the form of retaining pins 13, which allow positioning and orientation of the base member relative to the needle plate 7, the waste container 9 may also comprise retaining means for releasably securing to the throat plate 7. In particular, magnets 15 may be formed on the bottom 9a for producing a frictional connection with the needle plate 7. The container lid with the punching die 5b is in at least a defined orientation on the base element placed. If the base element, which comprises the base 9a and the side wall 9b or the side walls 9b, has a substantially square cross-section, then the container lid or die 5b can be placed on the base element in four defined orientations. Preferably, the cross section of the base element is substantially round, and the punching die 5b can be placed in different orientations on the base element. To specify one or more different orientations of the punch die 5b relative to the base member, these parts may include respective alignment means (not shown). In particular, the base element and the punching die 5b may, for example, in the mutual contact area have a toothing or coding, which allow the joining of these parts only in a single or alternatively in a plurality of predetermined orientations (not shown). It is particularly advantageous for the stamping die 5b to be in the form of a round plate which has indentations, bores or outstanding structures arranged uniformly distributed along its periphery on the underside (not shown). An annular shoulder 9c projecting radially inwardly slightly below the upper edge of the side wall 9b and on which the punching die 5b is placed are complementary protruding or recessed structures educated. Preferably, the size and arrangement of the magnets 15, which are used for attaching the base member to the throat plate 7, so determined that it can also be used to hold the punch die 5b on the base member, if they are also made of a ferromagnetic material such as steel is. The punching die 5b is marked analogously to the punch 5b with a marking which corresponds to that of the associated punch 5a. If the punch is not rotationally symmetrical, it must be fixed in a defined orientation on the needle bar 3. Preferably, this is done by means of a fastened to the needle bar rotating device, as shown in the EP2172585A1 is described. There codes or indexing means are provided, which clearly indicate the respective angular position. In an analogous manner, codes or indexing means can also be provided in the waste container 9, which clearly indicate the respective angular position of the punching die 5b relative to the base 9a or to the base element. For this purpose, the punching die 5b may, for example, have an arrow mark in the edge region which points to a marking on the side wall 9c corresponding to the respective rotary position (not shown). Before the beginning of punching, the arrow mark must be aligned with the marking that corresponds to the mark on the rotary device for the punch 5a. Instead of a presser foot adapted to the increased punching level L2 stamping foot 17 is attached to the Nähfussstange 19. This presses during the punching operation, the workpiece or the sheet to be processed 23 against the punching die 5b and then releases it again.

The workpiece or the fabric 23 can be clamped in an embroidery frame 21, in such a way that it does not rest on the stitch plate 7 in the sewing plane L1, but in the punching plane L2 on the punch die 5b. This can be achieved, for example, by connecting the embroidery frame 21 to the embroidery frame drive via an adapter, this adapter lifting the embroidery frame 21 by the height H1 of the waste container 9 (not shown). Preferably, however, the height H1 of the waste container 9 is set so that it corresponds to the height of the embroidery frame 21. For punching the sheet 23, the sheet 23 can be clamped in the embroidery frame 21 so that it rests in the punching plane L2 on the punch die 5b. Alternatively, the embroidery frame 21 can be turned, so that the already clamped fabric 23 is now in the punching plane L2. The cooperating with the sewing machine control of the control of the hoop (not shown), the arrangement of the hoop 21 on the hoop drive, for example, manually via a Input interface or automatically via appropriate sensors (not shown).

Claims (11)

Apparatus for punching a fabric (23) in a sewing machine, wherein the fabric (23) between the sewing machine head (1) and the needle plate (7) transversely to the needle bar axis N is displaced, characterized in that a punching tool with a punching die (5b ) and a in the form and size of the punching die (5b) tuned punch (5a) is connectable to the sewing machine, wherein the punch (5a) and / or the punching die (5b) relative to each other between a basic position and an end position are movable, wherein in the initial position between the punch (5a) and the punching die (5b), a gap is formed in which the sheet (23) is displaceable and positionable for punching, and wherein when moving from the basic position to the end position a piece of waste may be punched out of the sheet (23), and the punching tool comprises a waste container (9) for receiving punched out pieces of waste. Apparatus according to claim 1, characterized in that the punching die (5b) comprises a contact plate with an inlet opening (11) for the punch (5a), and that this contact plate as part of the waste container (9) or adjacent to the Waste container (9) is formed. Apparatus according to claim 2, characterized in that the contact plate is designed as a removable and / or replaceable lid of the waste container (9). Apparatus according to claim 3, characterized in that the waste container (9) is formed like a can and a base member having a bottom (9a) and a side wall (9b) comprises that below the upper edge of the side wall (9b) has an annular shoulder (9c) on the side wall (9b) projects inwardly, and that the contact plate on this shoulder (9c) can be placed and supported in at least one predetermined rotational position. Device according to one of claims 2 to 4, characterized in that the waste container (9) comprises holding means for positioning and releasably attaching to the needle plate (7) of the sewing machine. Apparatus according to claim 5, characterized in that said holding means at least one on the underside of the waste container (9) outstanding and in a corresponding opening (7a) in the throat plate (7) insertable retaining pin (13) and / or at least one magnet (15) for holding on the needle plate (7). Apparatus according to claim 6, characterized in that the at least one retaining pin (13) with an exact fit or with minimal play in the needle hole for the sewing needle in the throat plate (7) can be inserted, and that the retaining pin (13) and the inlet opening (11). for the punch (5a) are arranged coaxially or have a common axis of symmetry. Device according to one of claims 6 or 7, characterized in that the at least one retaining pin (13) is not rotationally symmetrical, and / or that a plurality of retaining pins (13) on the underside of the waste container (9) protrude, such that by positive engagement or the retaining pin (13) a non-rotatable mounting of the waste container (9) or at least the base member on the needle plate (7) is made possible. Device according to one of claims 6 to 8, wherein the at least one magnet (15) arranged on the base member of the container (9) and adapted for attachment to the needle plate (7), characterized in that this at least one magnet (15) is also designed for fastening the contact plate on the base element. A method of punching a sheet with a device according to any one of claims 1 to 9, characterized in that the waste container (9) by means of the holding means on the throat plate (7) is fixed, which clamps the sheet in an embroidery frame and the embroidery frame so with a connected to the sewing machine embroidery frame drive is connected, that the sheet is arranged in a plane parallel to the sewing plane L1 punching level L2 above the needle plate, and that the embroidery frame successively analogous to embroidering machining positions anfährt that the punching tool at these machining positions parts punched out of the fabric, and that these punched parts are received by the waste container (9). A method according to claim 10, characterized in that the punching operation is performed several times at a processing location, if the punching of a part is not possible with a punching operation.

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